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Questions tagged [gis]

A Geographic Information System (GIS) captures, stores, analyzes, manages, and presents data that are linked to location(s). The GIS Stack Exchange should be considered for questions with this tag.

According to Wikipedia:

A geographic information system (GIS), geographical information system, or geospatial information system is any system that captures, stores, analyzes, manages, and presents data that are linked to location(s). In the simplest terms, GIS is the merging of cartography, statistical analysis, and database technology.

There is a Stack Exchange site devoted to Geographic Information Systems.

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django.contrib.gis.db.backends.postgis vs django.db.backends.postgresql_psycopg2

If a gis application has some tables which don't have gis related columns, does the performance better when use multiple databases (django.db.backends.postgresql_psycopg2 and django.contrib.gis.db.backends.postgis) compared using…
zhigang
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WorldWind line of sight

I've found this example of how to render line of sight in WorldWind: http://patmurris.blogspot.com/2008/04/ray-casting-and-line-of-sight-for-wwj.html (its a bit old, but it still seems to work). This is the class used in the example (slightly…
mainstringargs
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From Voronoi tessellation to Shapely polygons

from a set of points I built the Voronoi tessellation using scipy: from scipy.spatial import Voronoi vor = Voronoi(points) Now I would like to build a Polygon in Shapely from the regions the Voronoi algorithm created. The problem is that the…
marcodena
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Where can I download a list of world cities and towns by ISO 3166-2 state code?

World countries and their standard codes are listed in ISO 3166-1. States (whatever are they called in different countries ("lands" in Germany, "federation subjects" in Russia etc.)) of the countries and their codes are defined in ISO 3166-2. But I…
Ivan
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Checking if a longitude/latitude coordinate resides inside a complex polygon in an embedded device?

I need the user to be able to draw a complex polygon on a map and then have the application check if a given longitude/latitude resides within that polygon. I was only able to find algorithms that were using a simple x/y cartesian coordinate system…
ChewToy
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How do I convert kilometres to degrees in Geodjango/GEOS?

I'm using the "buffer" method from the GEOS API to create a circle based on a point and a radius in GeoDjango, according to this answer: GeoDjango: How to create a circle based on point and radius As one commenter noted, you'll have to convert the…
Jonas
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Failed to resolve common open file gradle.build

I have been struggling with the past 6 hours over this one error, which i am not able to resolve.I imported the project directly from nextgis github. Please identify whats wrong and how to rectify it. here's the screen-shot of the error here the…
sid.s
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Shapefile reader in Python?

Are there any libraries that I can use to read a shp/shx/dbf/sbx set of files? I mainly need to extract some polygons but something that lets me extract any data that I want would be awesome.
Zameer Manji
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Country name for GPS coordinates

Is there an easy way to get the name of the country on whose territory a given point is located? I don't care too much about accuracy nor about ambiguities given by political disputes. Just need a good enough approximation.
ibz
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Plot circle with a certain radius around point on a map in ggplot2

I have a map with the 8 points plotted on it: library(ggplot2) library(ggmap) data = data.frame( ID = as.numeric(c(1:8)), longitude = as.numeric(c(-63.27462, -63.26499, -63.25658, -63.2519, -63.2311, -63.2175, -63.23623, -63.25958)), …
Shark167
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How do I find the center of a number of geographic points?

If I have a series of points as longitude and latitude, how would I calculate the center of all of those points?
dvorak
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Identify a linear feature on a raster map and return a linear shape object using R

I would like to identify linear features, such as roads and rivers, on raster maps and convert them to a linear spatial object (SpatialLines class) using R. The raster and sp packages can be used to convert features from rasters to polygon vector…
digitalmaps
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Find path by sea from coastal point A to coastal point B

I have the seemingly tricky challenge of trying to work out a path, by sea, from one sea port to another sea port. The eventual aim is to plot this on a Google (or Bing) Map as a polyline. The path needs to: Be plausible, as a ship can't go over…
NickH
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Find all coordinates within a circle in geographic data in python

I've got millions of geographic points. For each one of these, I want to find all "neighboring points," i.e., all other points within some radius, say a few hundred meters. There is a naive O(N^2) solution to this problem---simply calculate the…
conradlee
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Plotting static base map underneath a sf object

I'm trying to plot a static base map underneath my sf object (for print). When using ggmap I first get a lot of errors, then I can't seem to figure out how to chain the base map to my ggplot2 object with a geom_sf. library(sf) #…
Tdebeus
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